:root {
  --bg: #0d1117;
  --bg2: #161b22;
  --bg3: #21262d;
  --border: #30363d;
  --text: #e6edf3;
  --text2: #8b949e;
  --orange: #f7931a;
  --green: #3fb950;
  --red: #f85149;
  --blue: #58a6ff;
}
* { margin:0; padding:0; box-sizing:border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; display: flex; flex-direction: column; }
a { color: var(--orange); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Nav */
nav { background: var(--bg2); border-bottom: 1px solid var(--border); padding: 0 2rem; display: flex; align-items: center; justify-content: space-between; height: 60px; position: sticky; top: 0; z-index: 100; }
.logo { font-size: 1.4rem; font-weight: 700; color: var(--orange); display: flex; align-items: center; gap: .5rem; }
.logo span { font-size: 1.6rem; }
.nav-links { display: flex; gap: 1.5rem; list-style: none; }
.nav-links a { color: var(--text2); font-size: .95rem; transition: color .2s; }
.nav-links a:hover, .nav-links a.active { color: var(--orange); text-decoration: none; }
.hamburger { display: none; background: none; border: none; color: var(--text); font-size: 1.5rem; cursor: pointer; }

/* Main */
main { flex: 1; max-width: 1000px; margin: 0 auto; padding: 2rem 1.5rem; width: 100%; }
h1 { font-size: 2rem; margin-bottom: .5rem; }
h2 { font-size: 1.4rem; margin-bottom: 1rem; color: var(--text); }
.subtitle { color: var(--text2); margin-bottom: 2rem; font-size: 1.05rem; }

/* Cards */
.card { background: var(--bg2); border: 1px solid var(--border); border-radius: 12px; padding: 1.5rem; margin-bottom: 1.5rem; }
.card h3 { color: var(--orange); margin-bottom: .75rem; font-size: 1.1rem; }

/* Grid */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; margin-bottom: 2rem; }
.grid .card { margin-bottom: 0; transition: transform .2s, border-color .2s; }
.grid .card:hover { transform: translateY(-4px); border-color: var(--orange); }
.grid .card .icon { font-size: 2rem; margin-bottom: .75rem; }
.grid .card p { color: var(--text2); font-size: .95rem; line-height: 1.5; }

/* Forms */
label { display: block; color: var(--text2); font-size: .85rem; margin-bottom: .35rem; }
input, select { width: 100%; padding: .65rem .85rem; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; color: var(--text); font-size: 1rem; margin-bottom: 1rem; }
input:focus, select:focus { outline: none; border-color: var(--orange); }
button, .btn { background: var(--orange); color: #fff; border: none; padding: .7rem 1.5rem; border-radius: 8px; font-size: 1rem; cursor: pointer; font-weight: 600; transition: opacity .2s; display: inline-block; }
button:hover, .btn:hover { opacity: .85; }
.btn-outline { background: transparent; border: 1px solid var(--orange); color: var(--orange); }

/* Result */
.result { background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 1rem 1.25rem; margin-top: 1rem; }
.result .val { font-size: 1.5rem; font-weight: 700; color: var(--green); }
.result .label { color: var(--text2); font-size: .85rem; }
.positive { color: var(--green) !important; }
.negative { color: var(--red) !important; }

/* Gas */
.gas-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin-bottom: 1.5rem; }
.gas-card { text-align: center; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 1.25rem; }
.gas-card .speed { font-size: .85rem; color: var(--text2); text-transform: uppercase; letter-spacing: 1px; }
.gas-card .gwei { font-size: 2rem; font-weight: 700; margin: .5rem 0; }
.gas-card.low .gwei { color: var(--green); }
.gas-card.avg .gwei { color: var(--orange); }
.gas-card.high .gwei { color: var(--red); }

/* Table */
table { width: 100%; border-collapse: collapse; }
th, td { padding: .6rem .75rem; text-align: left; border-bottom: 1px solid var(--border); }
th { color: var(--text2); font-weight: 600; font-size: .85rem; }

/* Tip */
.tip-box { background: linear-gradient(135deg, #1a1500, #0d1117); border: 1px solid var(--orange); border-radius: 12px; padding: 1.5rem; text-align: center; margin-top: 2rem; }
.tip-box p { margin-bottom: .75rem; color: var(--text2); }
.tip-box .addr { font-family: monospace; font-size: .8rem; color: var(--orange); word-break: break-all; background: var(--bg); padding: .5rem; border-radius: 6px; display: inline-block; max-width: 100%; cursor: pointer; }
.tip-box .addr:hover { background: var(--bg3); }
.copied { color: var(--green) !important; }

/* Footer */
footer { text-align: center; padding: 1.5rem; color: var(--text2); font-size: .85rem; border-top: 1px solid var(--border); }

/* Loading */
.loading { color: var(--text2); font-style: italic; }

/* Responsive */
@media (max-width: 640px) {
  .hamburger { display: block; }
  .nav-links { display: none; flex-direction: column; position: absolute; top: 60px; left: 0; right: 0; background: var(--bg2); padding: 1rem 2rem; border-bottom: 1px solid var(--border); gap: 1rem; }
  .nav-links.open { display: flex; }
  .gas-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.5rem; }
}